Angle that is smaller than a right angle (less than 90Â°). Angle formed by two lines or two perpendicular planes that measures 90Â°. Symbol denoting that a straight line meets another at a right angle. Symbol denoting that two straight lines do not remain at a constant distance from one other. Symbol denoting that two straight lines remain at a constant distance from one another.
Constriction vs. Dilation. Constriction and dilation are opposite, but related, processes in the body. Whereas dilation is an opening or widening of a structure or passageway to increase material flow, constriction leads to a decrease in material flow by closing the passage.
Vasoconstriction is a narrowing of the blood vessels resulting from contracting of the muscular wall of the vessels. When blood vessels constrict, the flow of blood is restricted or slowed.It is the opposite of vasodilation, the widening of blood vessels.Factors causing vasoconstriction are called vasoconstrictor, also vasopressors or simply pressors. Vasoconstriction usually results in an increase of the blood pressure.Vasoconstriction may be slight or severe.t is the opposite of vasodilation, the widening of blood vessels. Factors causing vasoconstriction are called vasoconstrictor, also vasopressors or simply pressors. Vasoconstriction usually results in an increase of the blood pressure. Vasoconstriction may be slight or severe.